The Thoroughbreds handed sixth-ranked Socastee its first shutout of the season and rendered Memphis-bound star forward Justin Watson a non-factor in the game.
Both South Aiken goals came on free kicks after halftime. Junior Jose Mireles scored the first goal on a rebound from a Bret Van Pelt free kick 17 minutes into the second half. Van Pelt netted the other score 10 minutes later when his free kick deflected off the goalkeeper, hit the left post and crossed the goal line near the right post for a 2-0 lead.
South Aiken goalkeeper Chad Christensen made nine saves.
The Thoroughbreds will play their state quarterfinal game at home on Saturday.